WASHINGTON (WUSA9) - A year long, caught-on-camera, undercover WUSA9 test shows DC cabs repeatedly giving white passengers preferential treatment at a rate as high as one out of three cabs stopping for white passengers compared to African-Americans, but the chairman of DC's taxi commission calls it economic, not racial discrimination.

See below for contact information on District officials who can implement change.

Including the three cabs that just passed that man, over the past weeks, we tested 57 cabs.

I posed as a passenger at the same locations where we staged an undercover African-American rider...each of us wearing the same clothing and and uncercover cameras showing each receiving quite different treatment.

Taxi Commission Chair believes equal service is improving

"I think we've made improvement," said DC Taxi Commission Chairman Ron Linton whether taxis are more likely to pick up black passengers since our tests began in December 2012.

Linton questioned the sample size of our November-December 2013 test.

"How many did you test?" Linton asked - we told him we had tested about 50 in our most recent sample. "That is less than one percent."

WUSA9 has tested hundred of cabs for racial disparity

But over the past year, WUSA9 has tested hundreds of cabs.

Starting a year ago, in December 2012, our undercover crews watched 15% of DC cabs tested refuse our black passenger's destination - video shows one of them locking the doors in his face as the driver says, "I'm not going there."

The cabby then drove a hundred feet farther to our undercover white passenger and agreed to take the white man to the same destination he'd just refused the black man.

In February we, we tested every Saturday night for three weeks from sundown until two in the morning,, testing nearly a hundred taxis..and this time, tracking cabs passing women too.

25% of cabs in that test passed our black passengers in favor of undercover whites down the street.

In May we tracked more cabs passing black or blind passengers with service dogs at a failure rate of about 33%.

The same month, we tracked 48% of cabs tested passing blind passengers with service dogs and riders in wheel chairs.

Same cabs repeatedly stop for white passenger

But the same cabs never passed me.

DC taxi inspectors followed our operations twice, but there is no evidence they ever tracked racial disparity independently.

In July, we ran our undercover operations from midnight until four - when no taxi inspectors are on DC streets.

Taxi inspector shifts end at midnight.

We found 100% of 20 cabs tested failing basic rules like - no DC taxi license at all, those with licenses not posting the required proof with face ID cards, cabs without the required bill of rights showing how to complain and that couldn't print required receipts, with one Virginia cabby, illegally picking up fairs in DC acknowledging he knew he would get away with it because no one is enforcing the rules.

Taxi Commission Chair says he has no data to show conditions are improving

Except for discrimination against disabled passengers, our most recent test was tied for the highest failure rate we've documented during any undercover operations through the year.

When confronted with the observation that the numbers would make it seem that there's been no improvement for black passengers over the past year, Chairman Linton disagreed.

"Well, that's your opinion," Linton said saying the system has improved and black passengers are being picked up at a higher rate, but acknowledged he did not have data to support his belief. "Not at my fingertips."

Our black passengers had to hail 34 cabs for 23 rides. Me? For 23 rides...I had to hail 22 cabs...that's right...one cab, I didn't even have to hail.

Taxi Commission Chair says disparity is "not the racial thing"

DC's taxi commission chairman is clear that the practice is illegal, but he believes taxis are looking for better paying fairs and calls it economic not racial discrimination

"It's really not the racial thing that results in failure to haul," Linton said. "Most of it is economic."

He acknowledged drivers may be profiling by race, but said the decision process is motivated by a desire for better fares, calling it"an economic assumption."

He dismisses undercover operations, saying they are ineffective and says the commission relies on passengers to complain.

"The enforcement action has to have a complainant," Linton said. "The effective way to do this is for people to rise up."

Little comfort for some, like the lifelong DC resident we watched passed three times in a row who said that is his normal experience.

"This is every day," the man said as he got into a cab our white crew screamed to a halt.

Some drivers have defended the practice citing murders and violence against cabbies.

On the day of publication, taxi commission officials released new data saying this year, they've investigated more than 11OO complaints, and Taxi Inspectors have issued more than 8,000 tickets for violations ranging from illegal fares to refusing service.